Caracterização morfológica e expressão de receptores de imunidade inata e de hormônios sexuais no útero de cadelas com hiperplasia endometrial pseudoplacentacional

Abstract

Pseudoplacentational endometrial hyperplasia (PEH) is a dog uterine lesion that, although frequent, is little described. Studies verified high frequency of pyometra associated to PEH in dogs, suggesting that PEH can be related to pathogenesis of pyometra. The aims of the present study were: (1) analyze frequencies of PEH and cystic endometrial hyperplasia (CEH) in female dogs, considering age, size and breeds, and investigate if there is association between PEH and pseudopregnancy; (2) characterize the transcription levels and expression of Toll-like receptors (TLR) 1, 2 and 4 and alpha estrogen receptors (ESR1), progesterone receptors (PR) and prolactin receptors (PRLR) in canine uterus with PEH and investigate the inflammatory response of canine uterus with PEH against in vitro bacterial stimulus. Experimental design used for each aim were: (1) Uterus from 300 dogs were sampled and processed to histopathological analyses, lesions were identified, and frequencies statistically compared; (2): Uterus from dogs submitted to elective ovary-salpingo-hysterectomy were sampled and classified as normal (control group) and with PEH (PEH group). Uterine explants were obtained and submitted to in vitro stimulus with inactivated Escherichia coli for 6 and 12 hours of culture. Transcription levels of TLR1, 2 and 4, of ESR1, PR and PRLR, and interleukin-6 (IL-6) and CXCL8 were evaluated by RT-qPCR. Expression and localization of TLR4, ESR1, PR and PRLR were evaluated by immunohistochemistry. Production of CXCL8 was measured in supernatants from all explants by sandwich ELISA. Results obtained were: (1) PEH was more frequent between 4 to 12 years old, in large dogs than small dogs and less frequent in dogs from Terrier breed group including, in this study, Brazilian Terrier and Yorkshires. Additionally, PEH (66.3%) was more frequent than CEH (16.3%) and more often associated with pyometra (48.7%) than absence of uterine inflammation (35.2%). There were no association between PEH and pseudopregnancy. (2). Transcription levels and expression of PR and ESR1 were lower in uterus with PEH, and that expression of PRLR was higher in PEH uterus. No differences were detected in TLR1, 2 and 4 transcription levels or TLR4 expression. PEH uterus transcription levels of IL-6 had downregulation at 6 hours of stimulation, followed by upregulation at 12 hours of stimulation. Control group had minimal IL-6 response in transcription levels. Transcriptions levels of CXCL8 were similar in both control and PEH groups at 6 and 12 hours of stimulation. Supernatant concentrations were similar in control and PEH groups at 6 hours of stimulation. At 12 hours of stimulation, there was no production of CXCL8 in PEH group and proinflammatory response was maintained in the control group, being significantly higher. Conclusions were: (1) PEH is a frequent lesion and frequently associated to pyometra and deserves more attention. Additionally, PEH can have predisposing factors related to age, size, breed or breed group; (2) The pattern of transcription levels of TLR1, 2 and 4 was similar between PEH and normal uterus, and the transcription levels and expression of ESR1 and PR and expression of PRLR were different in uterus with PEH. Additionally, the proinflammatory response pattern was different in uterus with PEH than normal uterus, with shorter CXCL8 response and inversion of IL-6 response.